• Journal of Preventive Medicine and Public Health
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• 제34권3호
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• pp.269-276
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• 2001

Objectives : To evaluate the internal burden and hazardous effects associated with smoking in middle and high school students. Methods : We analysed urinary cotinine(U-cotinine) concentrations and the frequency of Sister Chromatid Exchanges (SCE). A comparison was done of U-cotinine concentrations and the frequency of SCE in peripheral lymphocytes across school levels (middle vs. high) and smoking types (direct: daily & occasional smoking, indirect; usual indirect & non-smoking), in 122 males. Results : The middle school student group comprised 6.8% daily smokers, 15.9% occasional smokers, 40.9% daily indirect smokers, and 35.4% nonsmokers, while the high school student group comprised 18.0%, 20.5%, 35.7%, and 21.8%, respectively. The U-cotinine concentration and the frequency of SCE among the middle school students were $79.11{\mu}g/l$ and 2.0 per cell, respectively, which were significantly lower than the $146.85{\mu}g/l$ (p=0.078) and 2.6 per cell (p=0.005) of the high school students. Among the 40 direct smokers, these two biomarkers were $236.66{\mu}g/l$ and 2.59 per cell, significantly higher than the $67.33{\mu}g/l$ (p=0.0001) and 2.1 per cell (p=0.003) among indirect smoking groups. The variation in individual U-cotinine concentration ranged widely in both the indirect and direct smoking groups. Conclusion : Urinary cotinine concentrations and the frequency of Sister Chromatid Exchange seem to objectively and effectively evaluate student exposure whether it was direct or indirect smoking. Consequently, these biomarkers may be useful in monitoring the objective efficacy of anti-smoking programs in adolescent populations.

• Journal of the Korean Wood Science and Technology
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• 제43권4호
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• pp.411-420
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• 2015

동일 수종이라도 생장지역과 영급에 따라 수형 또는 재질의 차이가 존재하고, 이러한 차이는 형성층 활동에 따른 목부세포의 양과 질이 다르기 때문에 생기게 된다. 본 연구는 소광리와 안면도에서 자라는 소나무를 대상으로 형성층 활동의 계절적 변화를 조사하여 소나무 목재의 재질 차이를 분석하기 위한 기초자료를 마련하기 위해 수행하였다. 형성층 활동 분석 결과, 소광리 5영급 임분은 목재세포 분열을 4월 중순에 시작하였으며, 안면도는 5영급과 9영급 모두에서 4월 초에 시작하는 것으로 조사되었다. 소광리 9영급의 경우는 5월 중순에서 6월 중순으로 조사되었다. 형성층에서 세포분열이 종료되는 시기는 소광리 9영급을 제외하고 소광리와 안면도 모두 10월 중순부터 10월 말로 조사되었다. 소광리 9영급의 형성층 내 세포분열 종료는 10월 초였다. 형성층의 계절별 활동을 조사한 결과, 소광리의 형성층 분열기간이 안면도보다 짧게 나타났다. 반면, 소광리 소나무의 형성층으로부터 분열된 세포 수는 안면도보다 더 많은 것으로 나타났다.

• 인터넷정보학회논문지
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• 제11권4호
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• pp.23-32
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• 2010

본 논문에서는 해쉬 기반 RFID 태그를 위한 보안성이 향상된 인증 프로토콜을 제안하고, 제안한 인증 프로토콜 기반으로 한 RFID 태그의 디지털 코덱을 설계한다. 제안한 프로토콜은 태그와 back-end 서버 사이에서 3-way 질의 응답 인증 프로토콜을 기본으로 하고 있으며, 안전한 인증 메커니즘을 구현하기 위해, ISO/IEC 18000-3 표준에서 규정된 3가지 타입의 프로토콜 패킷을 개선된 형태로 수정한다. 제안한 방법은 Man-in-the-middle과 Replay attacks과 같은 능동 공격의 방어에 특히 유효하다. 제안된 프로토콜의 효과를 검증하기 위하여 RFID 태그에서의 디지털 코덱은 Verilog HDL을 사용하여 설계하였고 Hynix $0.25\;{\mu}m$ standard-cell library을 갖춘 Synopsys Design Compiler을 이용하여 합성하였다. 보안 분석 및 실험결과를 통해, 본 논문에서 제안된 방법이 사용자의 데이터 보안, 태그 익명성, Man-in-the-middle attack 예방, replay attack, 위조방지 및 위치 추적 등에 서 성능이 개선됨을 보였다.

• Child Health Nursing Research
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• 제16권1호
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• pp.56-65
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• 2010

Purpose: This study was done to identify factors influencing cell phone addiction in adolescents. Methods: The participants were 548 adolescents in two middle schools and four high schools. Data were collected through self-report questionnaires which were constructed to include a cell phone addiction scale, an impulsiveness scale, media specific factors, and cell phone use. The data were analyzed using the SPSS program. Results: Of the adolescents, 88.7% reported being average users, 8.4%, heavy users, and 2.9%, cell phone addicted. Cell phone addiction was significantly correlated with impulsiveness and media specific factors. Significant factors influencing cell phone addiction were gender, sending and receiving text messages on weekends, monthly call charges, impulsiveness, recreational reasons, and cultural reasons. Conclusion: The above findings indicate that cell phone addiction in adolescents is influenced by gender, text message use, call charges, impulsiveness and media specific factors. Therefore the development of prevention and management programs for cell phone addiction in adolescents should be based on these factors which influence cell phone addiction.

• 한국동물생명공학회지
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• 제34권1호
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• pp.2-9
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• 2019

Because mesenchymal stem cells (MSCs) maintain distinct capacities with respect to self-renewal, differentiation ability and immunomodulatory function, they have been highly considered as the therapeutic agents for cell-based clinical application. Of particular, differentiation condition alters characteristics of MSCs, including cellular morphology, expression of gene/protein and cell surface molecule, immunological property and apoptosis. However, the previous results for differentiation-related apoptosis in MSCs have still remained controversial due to varied outcomes. Therefore, the present study aimed to disclose periodical alterations of pro- and anti-apoptosis in MSCs under differentiation inductions. The human dental pulp-derived MSCs (DP-MSCs) were differentiated into adipocytes and osteoblasts during early (1 week), middle (2 weeks) and late (3 weeks) stages, and were investigated on their apoptosis-related changes by Annexin V assay, qRT-PCR and western blotting. The ratio of apoptotic cell population was significantly (p < 0.05) elevated during the early to middle stages of differentiations but recovered up to the similar level of undifferentiated state at the late stage of differentiation. In the expression of mRNA and protein, whereas expressions of pro-apoptosis-related makers (BAX and BAK) were not altered in any kind and duration of differentiation inductions, anti-apoptosis marker (BCL2) was significantly (p < 0.05) elevated even at the early stage of differentiations. The recovery of apoptotic cell population at the late stage of differentiation is expected to be associated with the response by elevation of anti-apoptotic molecules. The present study may contribute on understanding for cellular mechanism in differentiation of MSCs and provide background data in clinical application of MSCs in the animal biotechnology to develop effective and safe therapeutic strategy.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1336-1338
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• 1994

Cell fusion device is an artificial equipment which fuses electrically two types of cells fed from the respective micropump to the fusion chamber by electric pulses. In this case, the detective sensor of flowing cell, along with passage, is required to control the time of pulses applied to cell and the injection of cells which are fed from inlet to micropump. There are two methods of detection of flowing cell; optical, impedance method. The difference of output for optical sensor is about 426mV for 805nm wavelength. about 37mV for 665nm wavelength. In impedance method, sensor output is 132.33mV at middle point and 117.10mV at edge point in the channel. Experimental results show that the optimal frequency range of sensor output is Iron 50Hz to 400Hz.

• 한국식품영양과학회지
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• 제22권4호
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• pp.500-509
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• 1993

Pectins present in the primary cell walls and middle lamellae of plant cell walls are extracted by water, cheating agents, acid or alkali solutions. However, some neutral contaminating components are extracted in conjunction with pectins during the extraction process. Thus, the accurate characterization of physi-cochemical properties of pectins necessitates to get rid of the impurities. In this review, dialysis, alcohol precipitation, ion exchange chromatography and metal precipitation were compared as procedures to purify the pectin extracts. In addition, the chemical methods to analyze pectins are discussed in terms of three major chemical constituents, i.e., anhydrogalacturonic acid, methoxyl groups and neutral sugars.

• Child Health Nursing Research
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• 제16권4호
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• pp.304-313
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• 2010

Purpose: This study was done to develop an educational needs scale for the prevention of cell phone addiction and to investigate the educational needs for prevention of cell phone addiction in Korean adolescents. Methods: The participants were 609 adolescents in one middle school and two high schools. Data were collected through self-report questionnaires, and analyzed using the SPSS program. Results: Twenty items regarding the educational needs for prevention of cell phone addiction were selected for the final scale, and categorized into 3 factors (diagnosis and management, properties, and definition and actual condition) which explained 61.09% of the total variance. The educational needs for the prevention of cell phone addiction in adolescents were moderate, with items related to diagnosis and management ranked as most important. The educational needs for prevention of cell phone addiction varied by gender, grade, academic achievement, perception of health status, satisfaction with school, and text messaging participants. Conclusion: The findings indicate that educational needs for diagnosis and management of cell phone addiction ranked as most important in adolescents. Therefore, programs related to the prevention and management of cell phone addiction based on the educational needs of adolescents should be provided.

• Human Ecology Research
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• 제52권5호
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• pp.519-528
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• 2014

This study explores how the main variables of youth going through a transition period (parents' nurturing behavior, the youth's self-esteem and ego resilience, the peer group relationships) affect the youth's school adjustment. It also analyzes the effects of theses variables on the youth's dependence on cell phones, which are considered a necessity in modern society. This research is verified by using a structure model verification method based on data from the Korean Children Youth Panel Study. According to the research, first, 1st-year students in middle school show better adjustment to their school life and less dependence on cell phones when they have a stronger sense of self-esteem and ego resilience; further, it is revealed that cell phone dependence has an indirect influence on the school life of these children. Second, they tend to show better adjustment to their school life and less dependence on cell phones when their parents' nurturing behaviors are more positive. Third, these children tend to depend more on cell phones when they have a positive peer group relationship, Moreover, cell phone dependence has an indirect influence on their school life. When considering the impact of cell phone to youth in modern society, need to prepare proper training program for correct uses and preventing from addiction.

• Applied Microscopy
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• 제30권3호
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• pp.265-272
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• 2000

낙지 Octopus minor의 상완 신경절을 광학현미경과 전자현미경을 통해 관찰한 결과 다음과 같은 결론을 얻었다. 낙지의 상완신경절은 각각의 흡반 밑에서 둥근 형태로 관찰되었는데 그들의 크기는 흡반의 크기에 비례하였다. 둥근 형태의 상완신경절은 피질부와 수질부 두 부분으로 구분되었던 바, 피질부에서는 신경세포의 집단이, 수질부에는 신경망이 위치해 있었다. 신경세포의 집단에서는 3종류(소, 중, 대형)의 신경세포들이 관찰되었는데 소신경세포는 직경이 $0.9{\mu}m$정도인 둥근 형태의 작은 세포인데 비해 중신경세포는 직경 $1.6\times1.3{\mu}m$정도인 타원형세포였다. 대신경세포는 직경이 $2.8{\mu}m$정도 크기의 난원형의 큰 세포로 확인되었고 이들 3종류의 세포들은 모두 전자밀도가 낮아서 밝게 관찰되었으며 세포소기관의 발달은 미진하였다. 또한 중신경세포인 경우에는 $0.6\times0.4{\mu}m$정도 크기의 전자밀도가 중등도인 방추형 신경교세포에 의해 둘러싸여 있었다. 수질부의 신경망에서는 다양한 크기의 수상돌기와 축색돌기들이 복잡한 그물형태를 하고 있었다. 이들은 돌기내에서 4종류의 화학연접소포 (chemical synaptic vesicle)들을 소지하고 있었는데, 전자밀도가 매우 높고 직경이 100 nm 정도인 electron-dense synaptic vesicle과 전자밀도가 중등도이며 직경이 90nm 정도인 median electron-dense synaptic vesicle 그리고 중앙에 전자밀도가 높은 둥근 핵을 포함하는 직경 90nm정도의 electron-dense cored synaptic vesicle등이 관찰되었다. 그러나 전자밀도가 투명한 연접소포(electron-lucent synaptic vesicle)는 직경이 50nm정도로 가장 작은 형태를 하고 있었다.